A diet high in fiber benefits health. Fiber adds bulk to the stool to alleviate constipation. It increases food volume without increasing caloric content. Fiber adsorbs water and forms a gel-like composition during digestion, slowing the emptying of the stomach and intestinal transit, shielding carbohydrates from enzymes, and delaying absorption of glucose by the gastrointestinal tract. Fiber consumption can lower total and LDL cholesterol.
Total Fiber is the sum of Dietary Fiber and Functional Fiber. Dietary Fiber consists of nondigestible carbohydrates and lignin that are intrinsic and intact in plants. Functional Fiber consists of isolated, nondigestible carbohydrates that have beneficial physiological effects in humans (Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients), 2005, Chapter 7: Dietary, Functional and Total fiber. U.S. Department of Agriculture, National Agricultural Library and National Academy of Sciences, Institute of Medicine, Food and Nutrition Board).
The composition of dietary fiber varies greatly depending on the source (Cummings, What is fiber in “Fiber in human nutrition”, 1976, 1-23). Fibers from fruits and vegetables such as apples, citrus, sunflowers, sugar beet are rich in pectin; fibers from grains such as oat, barley, wheat are rich in β-glucan; cellulose is one third or less of the total fiber in most foods, except for legumes, in which it was about one half; gum is usually present in seed (Marlett, J Am Diet Assoc. 1992, 92:175-86; Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients), 2005, Chapter 7: Dietary, Functional and Total fiber. U.S. Department of Agriculture, National Agricultural Library and National Academy of Sciences, Institute of Medicine, Food and Nutrition Board). According to the U.S. Department of Agriculture, most fiber components such as gum and cellulose can be classified as Dietary Fiber or Functional Fiber, depending on whether it is naturally occurring in food (Dietary Fiber) or added to foods (Functional Fiber).
The composition of fiber can be broadly separated into two categories: (1) soluble and (2) insoluble. Soluble fiber dissolves in water. Insoluble fiber does not dissolve in water. Both soluble and insoluble dietary fiber pass from the small intestine to the large intestine only affected by their absorption of water (insoluble fiber) or dissolution in water (soluble fiber). Cellulose, lignin, xylan, etc. are insoluble fiber, while dextrin, glucan, gum, inulin, lactulose pectin, starch, etc. are soluble fiber.
According to published papers (Behall et al. 1989, Diabetes Care 12:357-364; Spencer et al. 1991, J Nutr 121:1976-1983; Greger J L, J Nutr. 1999, 129:1434S-5S; Coudray et al. J Nutr. 2003, 133:1-4; Raschka et al. Bone 2005, 37 (5):728-735; Scholz-Ahrens et al. J Nutr. 2007, 137 (11 Suppl):25135-25235), nondigestible oligosaccharides have been shown to increase the absorption of several minerals (calcium, magnesium, in some cases phosphorus) and trace elements (mainly copper, iron, zinc). The stimulation of absorption was more pronounced when the demand for minerals was high. How fibers mediate this effect include different mechanisms such as acidification of the intestinal lumen by short-chain fatty acids increasing solubility of minerals in the gut, enlargement of the absorption surface, increased expression of calcium-binding proteins mainly in the large intestine, etc.
Meanwhile the study by Shah et al. (Diabetes Care, 2009, 32:990-995) showed that fiber does not significantly affect the intake of calcium and other minerals. Reinhold at al. showed that dietary fiber from wheat and maize may block iron absorption (The American Journal of Clinical Nutrition, 1981, 34:1384-1391), but Cook et al. showed that inhibition of iron absorption is a not a universal property of fiber (Cook et al., Gastroenterology, 1983, 85:1354-1358).
Different functional fiber components have been shown to exhibit different benefits (Dietary Fibre: Components and functions, edited by Salovaara, Gates and Tenkanen, 2007). For example, concentrated oat β-glucan and gum Arabic lowers serum cholesterol in humans (Queenan et al., Nutrition Journal 2007, 6:6; Ross et al., Am J Clin Nutr, 1983, 37: 368-75).
Metal ions such as calcium acetate or carbonate, magnesium and lanthanum carbonate, and aluminum carbonate or hydroxide have been used to treat hyperphosphatemia in chronic kidney disease (CKD) for many years (Daugirdas et al., Semin Dial, 2011, 24:41-49). Compounds based on iron ions such as polynuclear iron(III)-oxyhydroxide and ferric citrate are in development for treating hyperphosphatemia in CKD (Phan et al., J Pharmacol Exp Ther, 2013, 346:281-289; Lida et al. Am J Nephrol, 2013, 37:346-358). These metal ions bind phosphate in the GI, but also get absorbed into the body and often cause undesirable systemic side effects. For example, phosphate binders based on calcium ions are known to increase hypercalcemia, and aluminum ions are known to cause aluminum toxicity.
Many metal ions are important for health, but most also are toxic when present at higher than normal concentrations. It would be of value to create novel compositions using a functional fiber component and metal ions that have favorable properties for therapeutic and nutritional use. Such compositions that bind undesirable elements such as phosphate in the GI without systemic exposure (i.e. non-absorbable) will provide substantial benefits.
Metal ion absorption mainly occurs in the small intestine. Many studies have been done for the absorption of calcium and iron. Absorption of dietary iron is a variable process. The amount of iron absorbed compared to the amount ingested typically ranges from 5% to 35% for heme iron, depending on types of iron used. (Monson E R., J Am Dietet Assoc. 1988; 88:786-790). The absorption for non-heme iron ranges from 2% to 20% for iron in plant foods such as rice, maize, black beans, soybeans and wheat. (Tapiero H, Gate L, Tew K D., Biomed Pharmacother. 2001; 55:324-332).
Preparation of complexes of carbohydrates/polysaccharides such as dextran, dextrose, maltose, sucrose, and fructose with iron compounds have been disclosed in many patents and publications, which typically concern an absorbable composition in the GI tract used to increase systemic iron delivery to treat iron deficiency anemia.
Studies have shown that these iron-carbohydrates greatly enhance iron absorption in the GI tract and are useful for treating iron deficiency and anemia (Hall and Ricketts, Journal of Pharmacy and Pharmacology, 1968, 20:662-664; Pabón et al., Arch Latinoam Nutr. 1986, 36:688-700).
Spengler et al. in 1994 (Eur. J. Clin. Chem. Clin. Biochem., 1994, 32:733) describes a method for preparing an insoluble iron(III) oxide hydroxide porous support by linking FeCl3.6H2O to dextran using NaOH as the catalyst. WO 2009/078037 describes a process for manufacture of iron sucrose complex to treat anemia. U.S. Pat. No. 7,674,780 describes a process for preparing an iron-sucrose complex, substantially free of excipients, for providing an iron-sucrose complex co-precipitated with sucrose, and for providing iron-sucrose complexes in aqueous solution.
U.S. Publication 2008/0234226 mentions the use of iron(III) complex compounds with carbohydrates or derivatives thereof for the preparation of a medicament for oral treatment of iron deficiency states in patients with chronic inflammatory bowel disease, in particular Crohn's disease and colitis ulcerosa.
U.S. Publication 2010/0035830 describes iron-carbohydrate complex compounds which contain iron(II) in addition to iron(III), processes for their preparation, medicaments containing them, and the use thereof for treatment of iron deficiency anemia.
U.S. Pat. No. 5,624,668 describes ferric oxyhydroxide-dextran compositions for treating iron deficiency having ellipsoidal particles with a preferred molecular weight range of about 250,000 to 300,000 Daltons.
The textile industry uses particulates of iron oxides as pigments to dye fabrics. In addition, iron oxide is applied to textile fibers in an attempt to increase the conductivity of the synthetic fiber.
Biomass, either in its native state, or chemically modified, can be used to capture water pollutants and nutrients.
Studies have shown that iron adsorbed on synthetic filtration media or biomass can remove phosphates from water (Unnithan et al., J. Appl. Polym. Sci. 2002, 84:2541-2553; Han et al., 6th Inter-Regional Conference on Environment-Water, “Land and Water Use Planning and Management,” Albacete, Spain, 2003, pp. 1-11). Treating refined aspen wood fiber with iron-salt solutions demonstrated limited capacities to remove (ortho)phosphate from test solutions, but pre-treating fiber with carboxymethyl cellulose followed by ferrous chloride treatment improved the phosphate-binding capacity (Eberhardt et al. Bioresource Technology 2006, 97:2371-2376).
U.S. Pat. No. 6,022,619 describes a method of forming textile composites comprising coatings of iron oxides deposited on textile substrates, a method for the deposition of iron(III) oxides in status nascendi from an aqueous solution so as to form a coherent coating on a textile substrate.
U.S. Publication 2009/0181592 describes a multicomponent fiber having a metal phobic component and a metal philic component that may be used in fabrics and other products manufactured therefrom for economically imparting at least one of an antistatic quality, antimicrobial and antifungal efficacy, and ultraviolet and/or electromagnetic radiation shielding.
U.S. Publication 2011/0086097 describes a manufacture process for producing an iron-containing phosphate adsorbent based on starch and soluble carbohydrates, in particular, a process for manufacturing and isolating an iron(III)-based phosphate adsorbent which purportedly exhibits pharmacological properties.